Video programming is very popular and important in modem society and is widely used for a number of purposes such as education and entertainment. Because of its importance and popularity, there are many means and methods in use for distributing and recording video programming. For example, video programming is broadcast to television receivers over the air and through cable television systems. Video programming is also recorded and distributed on video tapes and disks. Video programming may also be transmitted as streaming data or a compressed file that moves over a computer network, such as the Internet. These many different methods and means of storing and distributing video programming attest to its importance and popularity.
In addition to wanting a large selection of readily available video programming, consumers and viewers also want video programming that is of the highest possible quality. The images as displayed on televisions, video monitors and other display devices should be as crisp and clear as possible. Consequently, much technology is devoted to devices and methods that enhance the resolution and/or appearance of a video image as displayed on a monitor or display device.
Frequently, the resolution or appearance of the image is limited, not by the abilities of the display device, but by the quality and quantity of information in the video signal that is used by the display device to create the video images. For example, television signals were originally analog signals and analog signals are still used in over-the-air broadcasting. However, digital signals can carry more data and consequently can provide a better, higher-resolution image. For this reasons, cable television systems frequently use digital signals to transmit high-quality video images. Similarly, DVDs (Digital Video Discs) use digital data to store high quality video images. DVDs are widely recognized as providing higher picture quality during playback than video tapes that use an analog video signal.
In any given video image, the resolution and resulting quality of the image is most evident at the edges of objects in the image. Frequently, an object is a different color, shade or texture than its background or otherwise has a visual transition at its edges. As used herein and in the appended claims, the term “visual transition” refers to any boundary between areas in a video image that is distinguishable to viewers as having one or more different visual characteristics.
If the quality of a video image is low, the image will tend to blur particularly around the visual transition, e.g., in color, shade, etc., that defines the edges of the object in the image. Consequently, the overall appearance of an image can be greatly enhanced by making the edges of objects in the image appear sharp and well defined. The higher the resolution of an image, the easier it is to define object edges and other visual transitions within the image.
Techniques for improving the appearance of object edges in video images using analog signals have been known. However, digital signals have traditionally relied simply on providing additional image data for all parts of the image to provide an adequate appearance, including across those visual transition that occur at object edges.
Consequently, there is a need in the art for a method and system for further enhancing the appearance of a video image generated from a digital video signal at the edges of objects and other visual transitions within the image.